The present disclosure relates generally to quantum dot-polymer nanocomposites for chemical vapor sensing. In particular, the subject application relates to quantum dot-polymer nanocomposite sensor arrays for detecting vapors of a defined group of chemical analytes. More in particular, the subject application relates to the incorporation of quantum dots into a polymer matrix to form a film wherein the polymer is known to be responsive to a selective group of chemical vapors. Thereby, when the film is placed into contact with a chemical vapor, interaction between functional groups on the polymer and the chemical generate changes in the polymer network. Expansion or contraction of the polymer network responsive to interaction of the polymer and chemical generate measurable changes in fluorescence by virtue of the incorporated quantum dots.
Quantum Dots (QDs) are semiconductor nanocrystals which are known for their unique size-tunable optical and electronic properties. For the past few decades, extensive amounts of time, energy, and funding have been devoted to research and development efforts exploring the use of quantum dots (QDs) in a variety of different areas, for example, biological labeling for imaging and monitoring and optical sensing for chemical and biological detection. In the context of chemical and biological sensing applications, QDs must be functionalized on their surfaces, or embedded in a solid state matrix to form a composite. This is necessary to avoid QD agglomeration and the consequent fluorescence quenching.
Attributed to their transparence in the ultraviolet-visible (UV-Vis) region of the electromagnetic spectrum, polymeric materials are suitable candidates to be utilized as matrices for quantum dot composites in optical sensing applications.
Current fluorescence sensor technologies for chemical and biological detection are based on detecting changes in fluorescence caused by either a reaction between an organic fluorophore and a target or fluorescence resonance energy transfer (FRET) between two chromophores. The major problem associated with sensing mechanisms which use organic fluorophores is the resultant photo-bleaching and with FRET, it is difficult to control operation conditions. Neither mechanism is suitable for use under ambient air conditions.
Therefore, there is a need for a chemical detection sensing system which is suitable for use in ambient air conditions and which is more sensitive and robust than conventional sensing mechanisms.
By incorporating quantum dots into a polymer network structure to form a nanocomposite sensor or a nanocomposite sensor array, the quantum dots act as optical indicators for optical sensing applications, namely for chemical vapor detection, classification and identification.